The Dysphotopsia Mystery
John J. Bussa, M.D.
Cataract Surgery
Cataract Surgery
Desirable Traits Foldable Lens
Inert (non reactive) with a memory
Thin – folds tight and goes through a smaller
incision
Square edge – reduces early, heavy capsule
clouding
Contributions to Visual Quality
Index of Refraction
Human lens 1.41
Higher indices spread white light across a
spectrum causing chromatic aberration
Chromatic Aberration
•  White light is separated into its component
wavelengths upon bending by a lens
•  The shorter, blue rays come to a focus
closer to the lens than the longer, red rays
Duochrome Test
Contributions to Visual Quality
Index of Refraction
Human lens 1.41
Higher indices spread white light across a
spectrum causing chromatic aberration
Reflectance
Contributions to Visual Quality
Index of Refraction
Human lens 1.41
Higher indices spread white light across a
spectrum causing chromatic aberration
Reflectance
Shape – Thinner and flatter, acts like a mirror
Contributions to Visual Quality
Index of Refraction
Human lens 1.41
Higher indices spread white light across a
spectrum causing chromatic aberration
Reflectance
Shape – Thinner and flatter, acts like a mirror
Square Edge – Can cause internal reflections
Impossible to Predict
•  Patient is unhappy
•  Takes up chair time
Positive Dysphotopsia
•  Patient has “added” visual images
Shimmering or pulsing lights (scintillations)
Rings
Arcs
Central Flashes
Streaks
Number of Patients
•  1 in 10 will notice some type of
dysphotopsia
•  Few will complain
True dysphotopsia comes from the lens
implant, but check other possible sources...
Check the C’s
Cornea - Dystrophy, dry, irregular
Cylinder – Astigmatism
Capsule
Clouds – Vitreous strands or floaters
CME – Macular edema
Do a careful refraction
Treat the residual sphere and cylinder
What the patient sees
Shimmering or pulsing light (scintillations)
This usually caused by backscatter from
the IOL combined with short eye
movements.
Seen more in high refractive index IOL.
Size of the IOL does not matter.
What the patient sees
Arcs
Patient perceives the edge of the IOL,
usually only at night
Usually resolves over time if the capsule
edge overlaps the IOL.
What the patient sees
Flare or streaks
This is a night time symptom. Correcting
minimal astigmatism with glasses often
fixes it. Also making the pupil a little
smaller.
What the patient sees
Central flash
Caused by a peripheral light source
reflecting off the internal edge of the IOL.
Rounding the edges or milling the edge
will reduce this.
The Perfect Surgical Result
What the patient sees
Haloes
Usually caused by a multifocal IOL which
produces halos around lights from IOL
transition zones. Also seen with corneal
irregularity (RK)
May be seen with large pupils and small
optic IOL.
Most patients adapt. Miotics help.
How the patient reacts
We can’t eliminate all unwanted images,
but we don’t have to.
Reassure the patient that he is not crazy.
Do not get angry.
Follow a plan.
How the patient reacts
Neuroadaptation is our friend. Time is on
our side.
Our brain is great at eliminating visual
perceptions…
our blind spot
backscatter off our natural lens
irregular pupils
retinal blood vessels
new glasses
How the patient reacts
The variable gain theory, and how we can
minimize it.
Managing Dysphotopsia
Create accurate expectations before
surgery instead of excuses afterward.
Warn of a healing process.
Warn of unwanted images as a part of the
healing, but they will go away over time.
This allows them to “turn down the gain”
Managing Dysphotopsia
Managing the problem surgically
Match the IOL to patient
Pupil
Cornea
Surface curvature
Edge design
Center the IOL
Capsule over the IOL edge
Managing Dysphotopsia
Try night time pupil constriction
Alphagan P
Pilocarpine
Managing Dysphotopsia
Careful with the capsule
Won’t solve true dysphotopsia
Makes IOL exchange very dangerous
IOL Exchange
•  Consider the size of the capsulorhexis
•  Consider the edge design, go rounded
•  Consider low index of refraction, rounded
surface IOL. Silicone material
Negative Dysphotopsia
•  Associated only with perfect surgery
•  Temporal darkness or temporal black
shadow
•  The most common type of dysphotopsia
Negative Dysphotopsia
•  Most believe it is caused by the IOL edge
•  Some believe it is the edge of the anterior
capsule
•  A few believe it may be due to a ring
scotoma
Negative Dysphotopsia
1.  Associated with many types of PC IOL’s,
all well centered and in the capsular bag.
2. Does not happen with poorly centered
implants.
3. Does not happen with implants placed in
ciliary sulcus or anterior chamber.
4. Stimulated by temporal light source and
goes away when the light is removed.
5.  Normal visual fields
6.  Symptoms present early usually go away
Negative Dysphotopsia
7. Dilate the pupil, problem resolves
8. Constrict the pupil, problem worsens
9. No medical therapy seems to work,
however surgical management can help
Treatment
The first 6 months…
Observe and reassure. We know what is
happening and most likely it will go away.
Glasses with thick temporal frame can
block light and reduce symptoms.
Treatment
After 6 months…
Surgical solutions are considered
Piggy back a second, low powered IOL
Displace the optic to in front of the anterior
capsule
Primary optic capture
Treatment of Negative Dysphotopsia: Reverse Optic Capture
(click link above to watch)